Head support unit with ramp structure and drive having the same

ABSTRACT

A head support unit includes a head used to record information in or reproduce the information from the recording medium, a suspension that supports the head, and a lift tab that is connected to the suspension, and slides on a sliding surface of a ramp loading unit which holds the head outside the recording medium in loading the head onto the recording medium and in unloading the head from the recording medium, wherein the lift tab inclines from a connection part with the suspension relative to a surface of the recording medium, and a contact position between the lift tab and the sliding surface moves on the lift tab as the suspension moves.

This application claims the right of foreign priority under 35 U.S.C.§119 based on Japanese Patent Application No. 2005-160509 filed on May31, 2005, which is hereby incorporated by reference herein in itsentirety as if fully set forth herein.

BACKGROUND OF THE INVENTION

The present relates generally to a head support unit, and a drive havingthe same. The inventive drive is suitable, for example, for a hard discdrive (“HDD”) ramp loading unit that holds a head outside a recordingmedium.

Available electronic information contents have explosively increasedwith the recent rapid technology developments, as in the Internet. Thus,larger-capacity magnetic storages, typified by HDDs, have beenincreasingly demanded to store such a large amount of information.

A slider mounted with a head floats above a disc for recording andreproducing in the HDD. As a relationship between the slider and thedisc at the time of activation and halt of the disc, referred to as aninterface, there are a contact start stop (“CSS”) system in which theslider contacts the disc when the disc stops and starts rotating, and aramp or dynamic loading system in which the slider retreats from thedisc at the time of stopping the disc and is held by a holder called aramp.

The CSS system would, however, cause crashes or damage the disc iffrictions increase at the time of stopping and sliding. In addition,since the slider is likely to stick to the disc, the CSS system requiresa texture process that forms fine convexes and concaves on the discsurface so as to prevent the absorption. This texture process increasescost, and becomes difficult particularly due to the reduced floatingamount of the slider in the recent higher recording density and theassociative demands for the flat disc surface.

Accordingly, the ramp loading system has recently attracted attentions.In the ramp loading system, a non-contact between the slider and thedisc when the disc starts and stops rotations causes no friction thatwould otherwise damage the disc or absorptions between them. Anadditional advantage is that the ramp loading system requires no textureprocess and reduces the head floating amount. In the ramp loadingsystem, a lift tab provided at the tip of a suspension that supports theslider slides on a sliding surface on the ramp while contacting the rampwith an elastic force in loading the slider on the disc and unloadingthe slider from the disc.

In the ramp loading system, the ramp projects above the outercircumference of the disc. Without this projection, the slider drops offbetween the ramp and disc in loading and unloading. On the other hand,the projection amount should be as small as possible because theprojection reduces the recording area on the disc. Although it isconceivable that the projection having a large inclination angle reducesthe projection amount, this configuration might cause high-speedcollisions and damages between the lift tab and ramp during unloading.

BRIEF SUMMARY OF THE INVENTION

Accordingly, it is an exemplary object of the present invention toprovide a head support unit and a drive having the same, which preventdamages of the ramp and lift tab, and maintain a wide effectiverecording area on a recording medium.

A head support unit according to one aspect of the present inventionincludes a head used to record information in or reproduce theinformation from the recording medium, a suspension that supports thehead, and a lift tab that is connected to the suspension, and slides ona sliding surface of a ramp loading unit which holds the head outsidethe recording medium in loading the head onto the recording medium andin unloading the head from the recording medium, wherein the lift tabinclines from a connection part with the suspension relative to asurface of the recording medium, and a contact position between the lifttab and the sliding surface moves on the lift tab as the suspensionmoves. According to the head support unit, when an inclination angle ofthe lift tab and arrangement of sliding surface are properly set, theprojection amount of the ramp loading unit above the recording mediumcan be made shorter than the conventional ramp loading apparatus thatuses a horizontal lift tab and fixes the contact position on the lifttab. As a result, the shorter horizontal distance makes smaller therecording area on the recording medium invaded by the inclined part thanthe conventional one. In addition, the head can be more quickly loadedonto and unloaded from the recording medium.

The lift tab may have an inclination angle that partially changes. Thisconfiguration can make shorter the projection amount than the lift tabthat maintains the inclination angle constant. For example, theinclination angle of the lift tab at a position at which the lift tabfirst contacts the sliding surface is greater than the inclination angleof the lift tab, such as 0°, at a position at which the head cannotrecord the information in or reproduce the information from therecording medium, in unloading the head from the recording medium. Thisconfiguration reduces not only the impact when the lift tab contacts theinclined surface in unloading, but also the projection amount by whichthe ramp loading unit projects above the recording medium. For example,the lift tab forms a line, a curve or a combination of plural curveswhen projected onto a plane parallel to a longitudinal direction of theinclined part. Preferably, the lift tab has a maximum inclination angleof 30° or smaller. This is because the inclination angle greater than30° requires a longer lift tab and the slider is likely to vibrate dueto its vibration characteristics.

The drive having the above ramp loading unit, such as a magnetic discdrive and a magneto-optic disc drive, constitutes another aspect of thepresent invention. In this drive, for example, the lift tab may inclinefrom the suspension so that the lift tab goes away from (or approachesto in another embodiment) the recording medium toward a tip of the lifttab, wherein the sliding surface is arranged so that a contact positionbetween the lift tab and the sliding surface moves on the lift tabtoward the suspension (or toward the tip of the lift tab in the otherembodiment) as the suspension moves from a position where the lift tabfirst contacts the sliding surface toward the ramp loading unit, inunloading the head from the recording medium.

Other objects and further features of the present invention will becomereadily apparent from the following description of the embodiments withreference to accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view of an internal structure of a hard disc drive(“HDD”) as one exemplary drive according to one aspect of the presentinvention.

FIG. 2 is an enlarged perspective view of a slider in the HDD shown inFIG. 1.

FIG. 3 is an enlarged perspective view of the ramp loading unit in theHDD shown in FIG. 1.

FIG. 4 is an enlarged plane view of the ramp loading unit in the HDDshown in FIG. 1.

FIG. 5 is an enlarged perspective view of a variation of the ramploading unit shown in FIG. 4.

FIG. 6 is a schematic sectional view showing a positional relationshipamong a ramp, a lift tab, and a slider shown in FIG. 1.

FIG. 7 is a schematic sectional view showing a positional relationshipbetween the lift tab and the ramp applicable to the HDD shown in FIG. 1.

FIG. 8 is a schematic sectional view showing a positional relationshipbetween the ramp and a shaft of a carriage applicable to the lift tabshown in FIG. 7.

FIG. 9 is a schematic sectional view for explaining an operation whenthe lift tab shown in FIG. 7 moves clockwise on the ramp shown in FIG.8.

FIG. 10 is a schematic sectional view showing a positional relationshipbetween a variation of the lift tab shown in FIG. 7 and the ramp.

FIG. 11 is a schematic sectional view showing a positional relationshipbetween a variation of the lift tab shown in FIG. 10 and the ramp.

FIG. 12 is a schematic sectional view showing another positionalrelationship between the ramp and the shaft of the carriage applicableto the HDD shown in FIG. 1.

FIG. 13 is a schematic sectional view showing a positional relationshipbetween the ramp shown in FIG. 12 and the lift tab applicable to theramp.

FIG. 14 is a schematic sectional view showing a positional relationshipbetween a variation of the lift tab shown in FIG. 13 and the ramp.

FIG. 15 is a schematic sectional view showing a positional relationshipbetween a variation of the lift tab shown in FIG. 14 and the ramp.

FIG. 16 is a schematic sectional view of a ramp according to anotheraspect of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

A description will be given of a HDD 1 according to one embodiment ofthe present invention with reference to the accompanying drawings. TheHDD 1 includes, as shown in FIG. 1, one or more magnetic discs 13 as arecording medium, a spindle motor 14, a magnetic head part, and a ramploading unit 100 in a housing 12. Here, FIG. 1 is a schematic plane viewof the HDD 1's internal structure. The number of magnetic discs 13 isillustratively one in this embodiment.

The housing 12 is made, for example, of aluminum die casting orstainless steel, and has a rectangular parallelepiped shape to which acover (not shown) for sealing the internal space is coupled. Eachmagnetic disc 13 in this embodiment has a high recording density, suchas 100 Gb/in² or higher, and is mounted on a spindle of the spindlemotor 14.

The spindle motor 14 rotates the magnetic disc 13 at a high speed, suchas 10,000 rpm, and includes a brushless DC motor (not shown) and aspindle as its rotor part. For example, when two magnetic discs 13 areused, a disc, a spacer, a disc, and a clamp are stacked in this order onthe spindle, and fixed by a bolt engaged with the spindle. Unlike thisembodiment, the magnetic disc 13 may be a disc having a hub without acenter hole, and the spindle may rotate the disc through the hub.

The magnetic head part includes a slider 19, and an actuator 21 thatserves as a mechanism for positioning and driving the slider 19.

The slider 19 includes, as shown in FIG. 2, a slider body 22 having anapproximately rectangular parallelepiped shape made of Al₂O₃—TiC(altic), and a head-device built-in film 24 united with at an airoutflow end of the slider body 22 and made of Al₂O₃ (alumina). The film24 contains a built-in read/write head 23. Here, FIG. 2 is an enlargedperspective view of the slider 19. The slider body 22 and head-devicebuilt-in film 24 define a floatation surface 25 opposing to a medium,i.e., the magnetic disc 13, for catching air current 26 generated fromthe rotating magnetic disc 13.

A pair of rails 27 extend on the floatation surface 25 from an airinflow end to the air outflow end. A so-called air-bearing surface(referred to as “ABS” hereinafter) 28 is defined at a top surface ofeach rail 27. The buoyancy is generated at the ABS 28 according to theact of the air current 26. The head 23 embedded in the head-devicebuilt-in film 24 exposes at the ABS 28. The floatation system of theslider 19 is not limited to this form, but may use a known dynamicpressure lubricating system, a known static pressure lubricating system,a known piezoelectric control system, and any other known floatationsystem. As discussed below, this embodiment uses a dynamic or ramploading system that retreats or unloads the slider 19 from the disc 13before the disc 13 stops, holds the slider 19 on the ramp loading unit100 outside the disc 13 in a non-contact manner between the slider 19and the disc 13, and drops or loads the slider 19 from the holding partonto the disc 13 in running the disc 13.

The head 23 includes a magnetoresistive (“MR” hereinafter)/inductivecomposite head that contains an inductive head device for writing binaryinformation into the magnetic disc 13 using a magnetic field induced bya conductive coil pattern (not shown), and a MR head device for readingresistance as binary information changing according to a magnetic fieldgenerated by the magnetic disc 13. The MR head device may use any type,such as a giant magnetoresistive (“GMR”) type including both a Currentin Plane (“CIP”) structure and a Current Perpendicular to Plane (“CPP”)structure, a tunneling magnetoresistive type (“TMR”), and an anisotropicmagnetoresistive (“AMR”) type.

Turning back to FIG. 1, the actuator 21 includes a voice coil motor (notshown in FIG. 1), a support shaft 15, and a carriage 16.

The voice coil motor includes can use any technology known in the art,and a detailed description thereof will be omitted. For example, thevoice coil motor includes a permanent magnet fixed onto an iron platefixed in the housing 12, and a mobile magnet fixed onto the carriage 16.The support shaft 15 is inserted into a cylindrical hollow in thecarriage 16, and arranged so that it extends perpendicular to the papersurface in FIG. 1 in the housing 12.

The carriage 16 includes a rigid arm 17 that can rotate or swing aroundthe support shaft 15, and a suspension 18 that is attached to a tip ofthe corresponding arm 17 and extends forward from the arm 17. Thesuspension 18 can be, for example, a Watlas type suspension made ofstainless steel, which uses a gimbal spring (not shown) to cantileverthe slider 19 and a lift tab 20 at the tip. The suspension 18 has awiring part connected to the slider 19 via gold ball bonding (“GBB”).FIG. 1 omits the wiring part. The sense current, read-in data, andread-out data are supplied and output between the head 23 and the wiringpart through the GBB connections. The suspension 18 applies an elasticforce to the slider 19 and the lift tab 20 against the surface of themagnetic disc 13.

The lift tab 20 extends along the center axis of the suspension 18 fromthe slider 19 opposing to the support shaft 15, and is engageable withthe ramp loading unit 100. The lift tab 20 has a boat shape that slideson a sliding surface 160, which will be described later and, forexample, is integrated with the suspension 18 and made of the samematerial as that of the suspension 18. The lift tab 20 slides on theramp loading unit 100 to load and unload the slider 19: The lift tab 20loads the slider 19 from the ramp loading unit 100 onto the magneticdisc 13 after the magnetic disc 13 starts driving, and unloads theslider 19 from the magnetic disc 13 to the ramp loading unit 100 so asto hold the slider 19 on the ramp loading unit 100 before the magneticdisc 13 stops driving.

Referring to FIGS. 1, 3 and 4, the ramp loading unit 100 is providedoutside or near the outermost circumference of the magnetic disc 13 andpartially projects from the disc 13. Here, FIGS. 3 and 4 are enlargedperspective and plane views of the ramp loading unit 100. Fordescription purpose of this embodiment, the ramp loading unit 100 usedfor both sides of one magnetic disc 13 is discussed, but the presentinvention is not limited to this embodiment.

Referring to FIGS. 3 and 4, the ramp loading unit 100 includes a fixturepart 110 fixed on a bottom wall of the housing 12 via screws, and a ramp120 coupled with the fixture part 110 outside the magnetic disc 13. Theramp 120 includes a base 122 coupled with the fixture part 110, and aguide part 124 that guides and holds the lift tab 20, and contacts thelift tab 20 slidably. The outer circumference of the magnetic disc 13 ispartially inserted into a U-shaped groove 126 at the top of the guidepart 124 As shown in FIG. 9, which will be described later, the contactposition between the lift tab 20 and the ramp 120 can be located at theproximal side of a connection part between the lift tab 20 and thesuspension 18. The guide part 124 in FIG. 4 can have a sufficient widthin FIG. 4.

The base 122 includes a cover 130 that prevents the vibrating lift tab20 from escaping from a holding part 140, which will be described later.An alternative embodiment shown in FIG. 5 replace the cover 130 with acover 130A that extends over the sliding surface 160 and prevents thelift tab 20 from vibrating on the convex and concave sliding surface 160and escaping from the sliding surface 160. Thereby, the ramp loadingunit 100 can prevent the slider 19 from colliding with the magnetic disc13 when the slider 19 is loaded over the magnetic disc 13 while the lifttab 20 vibrates. Here, FIG. 5 is a plane view of a variation of thecover 130 shown in FIG. 4.

The guide 124 includes a holding part 140, a sliding part 150, and apressure plate 190. While the holding part 140 and the sliding surface160 are also formed at the lower side of the guide part 124 and used foranother lift tab (not shown), only the upper side is addressed fordescription convenience.

The holding part 140 is a dent that holds the lift tab 20 that supportsthe slider 19. The holding part 140 is a home position for the lift tab20 in the ramp 120. While a dent shape of the holding part 140 is aU-shape that slightly opens at both sides in this embodiment, othershapes, such as a V shape, may be used.

The sliding part 150 has a sliding surface 160 arranged on such a levelthat the lift tab 20 contacts the sliding surface 160 with apredetermined elastic force. The sliding surface 160 has, as shown inFIG. 4, an arc shape with a predetermined width corresponding to an arclocus drawn by the lift tab 20, and includes a flat part 162 and aninclined part 164. When the guide part 124 is sufficiently wide, theshape of the sliding part 160 is not limited to the arc. The flat part162 is connected to the holding part 140, and extends parallel to asurface of the magnetic disc 13. The inclined surface 164 that inclinesfrom the flat part 162 to the magnetic disc 13 partially projects abovethe magnetic disc 13.

Referring now to FIG. 6, a detailed description will be given of arelationship among the lift tab 20, the slider 19, and the slidingsurface 160 of the ramp 120. Here, FIG. 6 is a schematic sectional viewshowing a positional relationship among the lift tab 20, the slider 19,and the sliding surface 160. In FIG. 6, 19-1 to 19-4 denote positions ofthe slider 19, 20-1 to 20-4 denote positions of the lift tab 20.

While the slider 19 is loaded on the disc 13, the slider 19 floats overthe disc 13 with a minute interval, and the lift tab 20 is spaced fromthe surface of the disc 13 while located at the position 20-1 as apredetermined height.

The lift tab 20 that is being unloaded contacts the inclined part 164first at the position 20-2, while the slider 19 at that time is locatedat the position 19-2. The position 19-2 is as high as the position 19-1from the surface of the disc 13.

As the suspension 18 moves further to the outer circumference of thedisc 13, the lift tab 20 goes up along the inclined part 164. At thistime, the suspension 18 generates a lifting force for lifting up theslider 19, and the force increases as the lift tab 20 climbs theinclined part 164. The force generated when the lift tab 20 ascends by apredetermined vertical distance V1 after the lift tab 20 contacts theinclined part 164 exceeds the compression force for compressing theslider 19 against the disc 13 with respect to a floating force of theslider 19. As a result, the slider 19 separates from the disc 13. Thelift tab 20 at this time is located at the position 20-3, while theslider 19 is located at the position 19-3.

Thereafter, the lift tab 20 further ascends along the inclined part 164,and moves to the flat part 162. The lift tab 20 at this time is locatedat the position 20-4, while the slider 19 is located at the position19-4.

When the slider 19 contacts the outer edge of the disc 13, at least oneof them get damages and the apparatus's reliability deteriorates.Therefore, a horizontal distance H1 between the position 20-2 and theposition 20-3 of the lift tab 20 must be smaller than a horizontaldistance H2 between the position 20-2 of the lift tab 20 and the outeredge part of the disc 13. When the inclined part 164 has a constantinclination angle θ, the horizontal distance H1 is expressed with thevertical distance V1 as H1=V1/tan θ. The projection amount by which theinclined part 164 projects above the disc 13 depends upon the horizontaldistance H1. This projection is necessary to prevent damages of theslider 19 and/or the disc 13, but decreases the recording area of thedisc 13. Therefore, the horizontal distance H1 must be as small aspossible to maintain the projection amount small.

In this respect, it is conceivable to increase the inclination angle θof the inclined part 164, but this would cause the lift tab 20 tocollide with the inclined part 164 at a high speed in unloading and theymight get damaged.

In prior art, the sliding surface 160 in FIG. 4 forms an arc that has acenter at the center of the shaft 15. When the locus of the contactposition between the lift tab 20 and the ramp 120 is projected onto theplane perpendicular to the shaft 15, the projected locus is the arcwhose center is located at the center of the shaft 15. The lift tab 20is horizontal to the disc 13, and the contact position between the lifttab 20 and the ramp 120 is fixed on the lift tab 20 even when thesuspension 18 moves to the outer circumference of the disc 13. On theother hand, this embodiment allows the contact position between the lifttab 20 and the ramp 120 to move to the proximal side of the lift tab 20as the suspension 18 moves to the outer circumference of the disc 13. Inorder to realize this action, this embodiment shifts the locus of thecontact position between the lift tab 20 and the ramp 120, whenprojected onto the plane perpendicular to the shaft 15, from the circlewhose center is located at the center of the shaft 15.

Referring now to FIGS. 7 to 9, a description will be given of oneembodiment of the present invention. In this embodiment, the distal endof the ramp 120 displaces by R₁ toward the inside of the circle C thathas a center of the center of the shaft 15, as shown in FIG. 8, and thelocus of the contact position between the lift tab 20 and the ramp 120from the position 20-2 is shifted, when projected onto the planeperpendicular to the shaft 15, to the inside of the circle whose centeris located at the center of the shaft 15. In addition, this embodimentinclines, as shown in FIG. 9, the lift tab 20 upwardly from the proximalend to the surface of the disc 13. The maximum inclination angle ispreferably 30° or smaller, because the inclination angle greater than30° requires a longer lift tab 20 and the slider 19 is likely to vibratedue to its vibration characteristics. Here, FIG. 7 is a schematicsectional view showing the lift tab 20 at the position 20-2 while it isbeing unloaded. FIG. 7 omits the base 122 etc. shown in FIG. 2. FIG. 8is a schematic plane view showing a relationship between the ramp 120and the shaft 15. FIG. 9 is a schematic sectional view showingdisplacements of the contact position between the lift tab 20 and theramp 120 as the lift tab 20 moves.

When the lift tab 20 moves from the position 20-2 to the position 20-3as shown in FIG. 9, the contact position between the ramp 120 and thelift tab 20 displaces from the position 120-2 to the position 120-3 anddescends by a vertical distance V2. As discussed, the horizontaldistance H1 is expressed as H1=V1/tan θ. When the vertical distance V2shown in FIG. 9 is considered, the horizontal distance H1 becomes(V1−V2)/tan θ, and reduces by V2/tan θ. The vertical speed of the slider19 becomes A·tan θ, where A is an in-surface speed of the head at theunloading time. Since the lift tab 20 inclines in this embodiment, thevertical speed of the slider 19 becomes faster than A·tan θ. Thereby,the projection amount of the ramp 120 above the disc 13 reduces, andmaintains a wide effective recording area of the disc 13.

Referring now to FIG. 10, a description will be given of anotherembodiment of the present invention. FIG. 10 is a schematic sectionalview of a lift tab 20A that is located at the position 20-2. The lifttab 20A bends so that a portion of the lift tab 20A closer to the tip ofthe lift tab 20A goes away from the disc 13. The lift tab 20A located atthe position 20-2 first contacts the ramp 120 through its tip. As thesuspension 18 further moves to the outer circumference of the disc 13,the contact position moves to the proximal side of the lift tab 20A. Dueto the operations similar to those in FIG. 9, this arrangement reducesthe projection amount of the ramp 120 above the disc 13, and maintains awide effective recording area of the disc 13.

This embodiment can also utilize the ramp 120 having the flat part 162but no inclined part 164. The bending lift tab 20A contacts and goesupon the ramp 120 as the suspension 18 moves in the outer circumferencedirection of the disc 13. Thereafter, as the suspension 18 further movesin the outer circumferential direction of the disc 13, the slider 19 canbe lifted from the disc 13. This embodiment does not require the ramp120 to have the inclined part 164 that should be formed with precision,facilitates the manufacture, and reduces the cost.

Referring now to FIG. 11, a description will be given of a lift tab 20Bas a variation of FIG. 10. Here, FIG. 10 is a schematic sectional viewof the lift tab 20B that is located at the position 20-2. The lift tab20B is similar to lift tab 20A in that the lift tab 20B bends so that aportion of the lift tab 20B closer to the tip of the lift tab 20A goesaway from the disc 13, but is different from the lift tab 20A in thatthe top of the lift tab 20B is parallel to the disc 13 or inclined sothat the tip is slightly higher.

Since the lift tab 20B contacts the ramp 120 at its flat or themoderately inclined portion, the lower contact force prevents damagesbetween the lift tab 20B and the ramp 120 when the lift tab 20B contactsthe ramp 120 at the position 20-2. In addition, the lift tab 20B stablycontacts the ramp 120 and moves up along the ramp 120, preventinginitial stick slips and biased abrasions of the ramp 120 and improvingthe loading and unloading reliabilities. Moreover, the abrasive powderis prevented from dropping on the disc 13 and lowering the recording andreproducing performance.

FIG. 12 is a schematic plane view for explaining still anotherembodiment of the present invention. This embodiment displaces by R₂ thedistal end of the ramp 120 to the outside of the circle C whose centeris located at the shaft 15, contrary to FIG. 8, and the locus of thecontact position between the lift tab 20 and the ramp 120 is shiftedfrom the position 20-2 to the outside of the circle whose center islocated at the center of the shaft 15 when the locus is projected ontothe plane perpendicular to the shaft 15. In addition, this embodimentinclines the lift tab 20 downwardly from the proximal end toward thesurface of the disc 13 as shown in FIG. 13. As the suspension 18 movesto the outer circumference of the disc 13, the contact position betweenthe lift tab 20C and the ramp 120 moves to the tip of the lift tab.Therefore, this embodiment also exhibits operations similar to those inFIG. 9.

As long as the locus of the contact position between the lift tab 20 andthe ramp 120 is as shown in FIGS. 8 and 12, the ramp 120 itself may belocated on the circumference of the circle C whose center is located atthe shaft 15.

Referring now to FIG. 14, a description will be given of still anotherembodiment of the present invention. FIG. 14 is a schematic sectionalview of a lift tab 20D that is located at the position 20-2. The lifttab 20D operates similar to the lift tab 20A. The lift tab 20D bends sothat a portion of the lift tab 20D closer to the tip of the lift tab 20Dapproaches to the disc 13. An angle between the lift tab 20D and thedisc 13 is small at the connection side with the suspension 18, and theangle increases toward its tip. The first contact position between theramp 120 and the lift tab 20D is located at the connection side betweenthe lift tab 20D and the suspension 18. As the suspension 18 furthermoves outside the disc 13, it gradually moves to its tip side. Thisarrangement reduces the projection amount of the ramp 120 above the disc13, and maintains a wide effective recording area of the disc 13.

One conceivable solution for lifting the slider 19 from the disc 13quickly is to increase the inclination angle of the inclined part of thelift tab 20D. However, this would cause in the lift tab 20D to suddenlychange the vertical speed, and increase the impact when the lift tab 20Dfirst contacts the ramp 120. As a result, they are likely to getdamages. Therefore, the processing that reduces the inclination angle ofthe inclined part of the lift tab 20D and increases the angle toward itstop improves the reliability.

FIG. 15 shows a lift tab 20E as a variation of the lift tab 20D, and thetip of the lift tab 20E bends so that it goes away from the disc 13toward its tip, preventing a likelihood of collisions due to the reducedclearance from the disc 13.

As discussed, the partially changed inclination angle of the lift tab 20improves the reliability to the ramp 120 and the lift tab 20. Similareffects are available from the partially changed inclination angle ofthe ramp 120 so that the angle is small at a position where the lift tab20 first contacts the ramp 120 in unloading, and then the angle may beincreased. If the moderately inclined portion of the lift tab 20contacts the ramp 120 when the lift tab 20 first contacts the ramp 120,the ramp 120 needs no inclined part and facilitates the manufacture.Conversely, instead of providing the lift tab 20 with the inclination,the inclination of the ramp may be partially changed for similareffects. Thus, the similar effects are available even when the featuresprovided to the lift tab 20 are replaced with the features provided tothe ramp 120. For example, as shown in FIG. 16, similar effects to thosein the above embodiment are available when the lift tab 20 is madehorizontal to the disc 12 in a zone H3 near the position 20-2 and theinclination angle of the ramp 120 in a zone H4 near the position 20-3 ismade greater than that in the zone H3.

The inclined part of the ramp 120 and the lift tab 20, when projectedonto a plane parallel to their longitudinal directions, may be made of aline, a curve or a combination of plural curves. The maximum inclinationangle is preferably 50° or smaller. The typical lift tab 20 is as wideas 0.307 mm and has an outer diameter of 0.2 mm. An inclination angle ofthe inclined part 164 of the ramp 120 greater than 50° hinders smoothloading and unloading actions due to contacts with the lift tab 20.

The pressure plate 190 projects from the ramp 120, has a prism shape,and includes upper and lower surfaces approximately parallel to asurface of the magnetic disc 13. The pressure plate 190 serves toprevent fluctuations of the slider 19.

The HDD 1 includes, as a control system (not shown) a control part, aninterface, a hard disc controller (referred to as “HDC” hereinafter), awrite modulation part, a read demodulation part, and a head IC. Thecontrol part covers any processor such as a CPU and MPU irrespective ofits name, and controls each part in the control system. The interfaceconnects the HDD 1 to an external apparatus, such as a personal computer(“PC” hereinafter) as a host. The HDC sends to the control part datathat has been demodulated by the read demodulation part, sends data tothe write modulation part. The control part or HDC provides servocontrol over the spindle motor 14 and (a motor in) the actuator 21. Thewrite modulation part modulates data and supplies data to the head IC,which data has been supplied from the host through the interface and isto be written down onto the magnetic disc 13 by an inductive head. Theread demodulation part demodulates data into an original signal bysampling data read from the magnetic disc 13 by the MR head device. Thewrite modulation part and read demodulation part may be recognized asone signal processing part. The head IC serves as a preamplifier.

In operation of the HDD 1, the control part (not shown) drives thespindle motor 14 and rotates the disc 13 in response to an instructionof the host, etc. The control part then controls the actuator 21 androtates the carriage 16 around the support shaft 15. Initially, the lifttab 20 is held by the holding part 140 in the ramp loading unit 100, butthe rotation of the carriage 16 moves the lift tab 20 from the holdingpart 140 to the sliding surface 160.

Next, the lift tab 20 moves to the disc 13 via the sliding surface 160,and the head 23 is sought onto a target track on the magnetic disc 13.The airflow associated with the rotation of the magnetic disc 13 isintroduced between the disc 13 and slider 19, forming a minute air filmand thus generating the buoyancy that enables the slider 19 to floatover the disc surface. On the other hand, the suspension 18 applies theelastic pressure onto the slider 19 in a direction against the buoyancyof the slider 19. The balance between the buoyancy and the elastic forcespaces the slider 19 from the disc 13 by a constant distance.

In a write time, the control part (not shown) receives data from thehost through the interface, selects the inductive head device, and sendsdata to the write modulation part through the HDC. In response, thewrite modulation part modulates the data, and sends the modulated datato the head IC. The head IC amplifies the modulated data, and thensupplies the data as write current to the inductive head device.Thereby, the inductive head device writes down the data onto the targettrack.

In a read time, the control part (not shown) selects the MR head device,and sends the predetermined sense current to the sense-current controlpart through the HDC. Data is amplified by the head IC based on theelectric resistance of the MR head device varying according to a signalmagnetic field, and is then supplied to the read demodulation part to bedemodulated to an original signal. The demodulated signal is sent to thehost (not shown) through the HDC, control part, and interface.

The instant embodiment reduces the projection amount of the ramp 120above the disc 13, and maintains a wide effective recording area.

When the read and write end, the control part controls the actuator 21and rotates the carriage 16 around the support shaft 15 from the innersurface to the outer surface on the magnetic disc 13. Thereby, the lifttab 20 unloads the slider 19 from the disc 13. Due to the adjustedinclination angles of the lift tab 20 and/or the ramp 120, the impact atthe contact time is similar to that in the conventional structure.Thereafter, the contact position between the lift tab 20 and the ramp120 moves so that the slider 19 lifts when the lift tab 20 moves alongthe sliding surface 160. The distance H1 by which the slider 19 ascendsfrom the disc 13 is shorter than that of the conventional structure.Thereafter, the lift tab 20 is held by the holding part 140. The cover130 restricts the perpendicular movements of the lift tab 20 in theholding part 140. The pressure plate 190 faces the free end of thesuspension 18 with a clearance of about 0.1 mm, and restricts abnormalfluctuations of the suspension 18 or abnormal displacements of theslider 19.

The control part (not shown) controls the spindle motor 14 and stops therotation of the magnetic disc 13. Unlike the CSS system, the ramploading system is less likely to cause crashes when driving of themagnetic disc 13 starts, since the frictional force is not applied tothe slider 19.

Further, the present invention is not limited to these preferredembodiments, and various modifications and changes may be made in thepresent invention without departing from the spirit and scope thereof.For example, the number of holding parts 140 and the number of slidingsurfaces 160 are variable in the ramp loading unit 100 depending uponthe number of discs 13 and the number of sliders 19. A type of theinventive recording medium is not limited to a magnetic disc and thepresent invention is applicable to an optical disc.

Thus, the present invention can provide a head support unit and a drivehaving the same, which prevent damages of the ramp and lift tab, andmaintain a wide effective recording area on a recording medium.

1. A head support unit comprising: a head used to record information ina recording medium or reproduce the information from the recordingmedium; a suspension that supports said head; an arm connected to thesuspension and configured to rotate the suspension around a shaft; and alift tab that is connected to said suspension, and slides on a slidingsurface of a ramp loading unit which holds the head outside therecording medium in loading the head onto the recording medium and inunloading the head from the recording medium, the lift tab extending ina radial direction of a circle having a center at a center of the shaftwhen the lift tab is projected onto a plane perpendicular to the shaft,wherein said lift tab inclines from a connection part with saidsuspension relative to a surface of the recording medium, and a contactposition between said lift tab and the sliding surface moves on the lifttab along a longitudinal direction of the lift tab as the arm rotatessaid suspension.
 2. The head support unit according to claim 1, whereinsaid lift tab has an inclination angle that partially changes.
 3. Thehead support unit according to claim 2, wherein the inclination angle ofsaid lift tab at a position at which said lift tab first contacts thesliding surface is greater than the inclination angle of said lift tabat a position at which the head cannot record the information in orreproduce the information from the recording medium, in unloading thehead from the recording medium.
 4. The head support unit according toclaim 1, wherein said lift tab has an inclination angle of about 0° at aposition where said lift tab first contacts the sliding surface, inunloading the head from the recording medium.
 5. The head support unitaccording to claim 1, wherein said lift tab forms a line, a curve or acombination of plural curves when projected onto a plane parallel to thelongitudinal direction of the lift tab.
 6. The head support unitaccording to claim 1, wherein said lift tab has a maximum inclinationangle of 30° or smaller.
 7. A drive comprising the head support unitaccording to claim
 1. 8. The drive according to claim 7, wherein saidlift tab inclines from said suspension so that said lift tab goes awayfrom the recording medium toward a tip of the lift tab, and wherein thesliding surface is arranged so that a contact position between the lifttab and the sliding surface moves on the lift tab toward the suspensionas the suspension moves from a position where said lift tab firstcontacts the sliding surface toward the ramp loading unit, in unloadingthe head from the recording medium.
 9. The drive according to claim 7,wherein said lift tab inclines from said suspension so that said lifttab approaches to the recording medium toward a tip of said lift tab,and wherein the sliding surface is arranged so that a contact positionbetween the lift tab and the sliding surface moves on the lift tabtoward the tip of said lift tab as the suspension moves from a positionwhere said lift tab first contacts the sliding surface toward the ramploading unit, in unloading the head from the recording medium.